How long to image the Ring Nebula with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 25 min (101 subs of 15 s) for a solid image of the Ring Nebula. A quick look takes 6 min; a showpiece 1 h 41 min. Under a Bortle 3 rural sky the solid figure drops to 16 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is small in the frame, about 28 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 4 min16 subs | 15 min61 subs | 1 h242 subs |
| Bortle 2Typical dark site | 4 min16 subs | 15 min62 subs | 1 h 02 min247 subs |
| Bortle 3Rural | 4 min16 subs | 16 min64 subs | 1 h 04 min256 subs |
| Bortle 4Rural / suburban transition | 4 min18 subs | 17 min70 subs | 1 h 10 min279 subs |
| Bortle 5Suburban | 5 min20 subs | 20 min79 subs | 1 h 19 min315 subs |
| Bortle 6Bright suburban | 6 min26 subs | 25 min101 subs | 1 h 41 min403 subs |
| Bortle 7Suburban / urban transition | 9 min36 subs | 36 min143 subs | 2 h 23 min571 subs |
| Bortle 8City | 13 min52 subs | 52 min208 subs | 3 h 28 min832 subs |
| Bortle 9Inner city | 22 min87 subs | 1 h 27 min347 subs | 5 h 47 min1,388 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 33 min of run time. The DWARF II’s battery (rated about 3 h) should cover it; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB-C PD power bank 10000mAh 18W18 W PD input; runs while charging.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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Everything that fits the DWARF II →
How it frames
The Ring Nebula is 1.4′ × 1′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it is small in the frame, about 28 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.
Filters
The Ring Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the DWARF II has no dual-band option: Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold. The figures above are for the Astro position, and a darker sky is the lever that remains.
About the Ring Nebula
A tiny, bright smoke ring. It is small in a smart scope but so bright per pixel that a few minutes show the ring; the faint outer halo is another matter.
M57, NGC 6720 · Planetary nebula in Lyra · magnitude 8.8 · 1.4′ × 1′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
About the DwarfLab DWARF II
The original pocket scope. 24 mm aperture and tiny 1.45 µm pixels mean it is slow per pixel, so bin or downsample and be patient.
15 s is the hard maximum in any mode; DwarfLab recommends EQ mode at 15 s. Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold.
The DWARF II uses fixed 15 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.
Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.
Have an image of the Ring Nebula from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Ring Nebula with the ZWO Seestar S50: 7 min from Bortle 6
- Ring Nebula with the ZWO Seestar S50 Pro: 8 min from Bortle 6
- Ring Nebula with the ZWO Seestar S30: 7 min from Bortle 6
- Ring Nebula with the ZWO Seestar S30 Pro: 8 min from Bortle 6
- Ring Nebula with the DwarfLab DWARF 3: 10 min from Bortle 6
- Ring Nebula with the DwarfLab DWARF mini: 8 min from Bortle 6
- Ring Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Ring Nebula with the Vaonis Vespera II: 8 min from Bortle 6
- Ring Nebula with the Vaonis Vespera Pro: 17 min from Bortle 6
- Ring Nebula with the Vaonis Vespera 3: 7 min from Bortle 6
- Ring Nebula with the Vaonis Vespera Pro 2: 16 min from Bortle 6
- Ring Nebula with the Unistellar eQuinox 2: 6 min from Bortle 6
- Ring Nebula with the Unistellar Odyssey: 28 min from Bortle 6
- Ring Nebula with the Celestron Origin: 5 min from Bortle 6
- Ring Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Ring Nebula · All targets for the DWARF II